Steering assembly for a human-driven vehicle, and human-driven vehicle

ABSTRACT

The steering assembly is applicable to a human-driven vehicle having a chassis ( 1 ) mounted on self-orienting wheels ( 2 ). The steering assembly comprises a steering unit ( 50   b ) with a steering wheel ( 4 ) installed on a mobile support and maintained out of contact with the ground by elastic means at an end ( 1   b ) of the chassis ( 1 ), and a control unit ( 50   a ) with a command member ( 7 ) in another end of the chassis. The units are connected by transmission devices ( 19, 20, 21 ). The command member ( 7 ) is manually operable to lower the steering wheel ( 4 ) against the force of said elastic means and to make the steering wheel ( 4 ) rotate with respect to a substantially vertical shaft when the wheel ( 5 ) is in contact with the ground to steer the vehicle. The elastic means automatically lift the steering wheel ( 4 ) when the manual operation of the command member ( 7 ) ceases.

TECHNICAL FIELD

The present invention relates to a steering assembly applicable to ahuman-driven vehicle provided with self-orienting wheels, such as, forexample, a shopping cart, a warehouse trolley, a hospital bed or cart,etc., for the purpose of providing the user with the possibility ofperforming a steering of said vehicle by means of a command membercontrolling an additional steering wheel. The present invention alsorelates to a human-driven vehicle provided with such device.

BACKGROUND OF THE INVENTION

International patent application WO-2006/037822-A1, belonging to thecurrent applicant, discloses a device for steering a self-orientingwheel of a human-driven vehicle, where the self-orienting wheel to beguided is one of the wheels on which the vehicle moves in normalconditions. The operation of the device is based on providing a steeringmechanism and a clutch mechanism which can optionally be operated tocouple said steering mechanism to a rotating support on which theself-orienting wheel is mounted. The mentioned steering and clutchmechanisms are distributed in a control unit fixed, for example, to apush bar located in a rear end region of the vehicle, and a steeringunit associated with the self-orienting wheel to be driven, which islocated, for example, in a front end region of the vehicle. The partialmechanisms housed in the control and steering units are mutuallyconnected by respective movement transmission devices, such as, forexample, Bowden type flexible cable and sheath assemblies. Elastic meanspush the clutch mechanism towards an uncoupled position and thementioned control unit includes a command member at the disposal of theuser to remotely operate the clutch mechanism against the force of saidelastic means and the steering mechanism.

The device of the mentioned international patent applicationWO-2006/037822-A1 is fully operative, although it has some aspects whichcan be improved. For example, the implementation of the clutch mechanismrequires an adaptation to the self-orienting wheel to be driven and, dueto the fact that there is a large variety of self-orienting wheelmodels, a specific design of part of the clutch mechanism is requiredfor each model if the device is to be applied to a variety ofpre-existing vehicles. Furthermore, the coupling of the clutch mechanismis only performed when the self-orienting wheel is in a predeterminedangular position in relation to a coupling part of the clutch mechanism,which forces the user to perform a certain maneuver with the vehicle inaddition to manually acting on the command member to carry out thecoupling.

Document EP-1238885-A1 discloses a carriage provided with self-orientingwheels, which includes an additional steerable and power-driven wheel atan end of the carriage. The mentioned orientable wheel is mounted on asupported connected to a mechanism operated by means of a handle whichallows lowering the support until putting the orientable wheel incontact with the ground, and raising the support to put the orientablewheel out of contact with the ground. The raising and lowering mechanismcomprises a tubular column fixed to the chassis of the carriage and aslide bar inserted in said tubular column, where the support of thewheel is fixed to the lower end of the slide bar and the handle isinstalled at the upper end of the tubular column to rotate with respectto a horizontal axis and connected to the upper end of the slide bar bymeans of an eccentric mechanism. The handle can thus be shifted betweena horizontal position and a vertical position to raise or lower theorientable wheel and can be rotated with respect to a vertical axis tovary the orientation of the orientable wheel. A locking mechanism allowslocking the handle in the horizontal position.

A drawback of the carriage described in the mentioned documentEP-1238885-A1 is that the control handle is located at the same end ofthe carriage where the orientable wheel is located, which is unsuitablefor a human-driven vehicle, such as a shopping cart, where the mostsuitable situation for a steering wheel is the front end region of thevehicle while the vehicle is generally pushed by the user by means of apush bar or another resistant structure located in the rear end regionof the vehicle.

DISCLOSURE OF THE INVENTION

The present invention provides a steering assembly for a human-drivenvehicle, said vehicle having a chassis with a first end region and asecond end region which are opposite to one another. The mentionedchassis is mounted on freely rotating wheels, where at least two of saidwheels, which are located in said second end region, are self-orientingwheels. The steering assembly comprises an additional steering wheelinstalled on a wheel support in the second end region of the chassis, amanually operable lowering mechanism for moving said wheel supportbetween a lifted position, in which said steering wheel is out ofcontact with the ground, and a lowered position, in which the steeringwheel is in contact with the ground, and a manually operable steeringmechanism for making the wheel support and with it the steering wheelrotate with respect to a steer shaft, which is in a substantiallyvertical position at least when the wheel support is in said loweredposition, to steer the vehicle.

First elastic means are arranged to push the wheel support towards saidlifted position, and to maintain it therein, and said lowering mechanismcomprises a command member which can be manually operated to move thewheel support towards the lowered position against the force of saidfirst elastic means. The mentioned lowering mechanism is configured tomove, as a consequence of a manual operation of the command member, thewheel support towards the lowered position, and maintain it therein,against the force of said first elastic means. The first elastic meansare arranged to return the wheel support to the lifted position whensaid manual operation of the command member ceases.

The mentioned command member is common for said lowering and steeringmechanisms and is located in said first end region of the chassis, andthe wheel support with the steering wheel is located in a second endregion of the chassis opposite to said first end region. Respectivefirst and second movement transmission devices are arranged to transmitmovements from the command member to the wheel support.

Preferably, each of said lowering and steering mechanisms has a firstpart installed adjacent to the command member and connected thereto insaid first end region of the chassis and a second part installedadjacent to the wheel support and connected thereto in the second endregion of the chassis. The mentioned first and second parts of thelowering and steering mechanisms are connected to one another by saidfirst and second movement transmission devices. The first parts of thelowering and steering mechanisms and said command member, which iscommon for both lowering and steering mechanisms, are integrated in acontrol unit configured to be fixed to a push member or to the chassisin the first end region so that the command member can be manuallyoperated by a user to remotely perform the lowering and rotationmovements of the wheel support from a position adjacent to said pushmember. The second parts of the lowering and steering mechanisms and thesteering wheel are integrated in a steering unit configured to be fixedto the chassis in the second end region. These two control and steeringunits are interconnected by the mentioned first and second movementtransmission devices, which are preferably formed by Bowden typeflexible cable and sheath assemblies.

With this construction, the steering assembly of the present inventionprovides the possibility of performing an optional steering of ahuman-driven vehicle provided with self-orienting wheels using anadditional steering wheel located at an end of the vehicle,advantageously the front end, by means of a command member located atthe disposal of the user at the opposite end of the vehicle,advantageously the rear end where the push member or another pushstructure is located. This arrangement allows the user to push thevehicle from behind, as is usual, and at the same time controloptionally and without an additional effort the direction of the frontend of the vehicle. Furthermore, this arrangement also allows theoptional control of the direction when the vehicle is pulled in anopposite direction.

The existence of the elastic means which automatically lift the steeringwheel putting it out of contact with the ground when the user stopsacting on the command member facilitates that the vehicle has the usualbehavior provided by the self-orienting wheels, allowing side movementswhen the user does not act on the command member. The steering assemblyof the present invention can be applied to human-driven vehicles of thetype which can be nested in one another when they are not in use toreduce space, and the fact that the additional steering wheel isautomatically placed in the lifted position by the mentioned elasticmeans assures the usual maneuverability of the plurality of nestedvehicles when they are moved together.

The steering assembly of the present invention can be supplied as a kitto be incorporated to pre-existing vehicles without needing to modify orsubstitute the original wheels of the vehicle as a result of providingthe additional steering wheel. Likewise, the steering assembly of thepresent invention can be easily integrated into the design of newhuman-driven vehicle models. In any case, the steering mechanism ispermanently coupled to the support of the additional steering wheel andto make use of the optional guiding capacity it is enough to operate thelowering mechanism to put the steering wheel in contact with the ground,without needing any additional coupling maneuver as in prior artdevices.

In a particular embodiment, the steering assembly of the invention isapplicable to a shopping cart of the type including a substantiallyhorizontal push member located in the first end region or rear region ofthe vehicle, said control unit is designed to be fixed directly to saidpush member or to the chassis in a position adjacent to the push member,and the command member has the form of a handlebar provided withcapacity of rotation on two crossed axes, where the command member ispositioned on one side of the push member facing the second end regionor front region of the chassis and has a pair of grips located at adistance from the push member selected so that said grips of the commandmember can be operated with one or more fingers of each hand at the sametime as the vehicle is pushed with the hands by means of the pushmember. In other words, the command member can be optionally operatedwhen considered necessary without needing to let go of the push member.Nevertheless, the command member is not limited to the form of ahandlebar and can adopt any other configuration, such as a lever orhandle provided with capacity of rotation on two axes, allowing it toadapt to vehicles which do not have a push member.

The control unit comprises a base body which can be fixed to the pushstructure or member, or to the chassis of the vehicle. A coin-operatedlocking device is operatively housed in said base body to allow theimmobilization of the vehicle with respect to another vehicle with asimilar coin-operated locking device, or with respect to an anchoringpoint fixed in relation to the ground.

BRIEF DESCRIPTION OF THE DRAWINGS

The previous and other features and advantages will be more fullyunderstood from the following detailed description of severalembodiments with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a steering assembly according to anembodiment of the present invention applied to a chassis of ahuman-driven vehicle exemplified by a shopping cart;

FIG. 2 is a perspective view of a control unit and a steering unitmutually connected by flexible movement transmission devices form thesteering assembly of FIG. 1;

FIG. 3 is a cross-sectional view of the control unit taken through avertical mid-plane, where a command member is in an inactive positioncorresponding to the lifted position of a steering wheel of the steeringunit shown in FIG. 5 or in FIG. 11;

FIG. 4 is a cross-sectional view of the control unit taken through avertical mid-plane, where the command member is in an active positioncorresponding to the lowered position of the steering wheel of thesteering unit shown in FIG. 6 or in FIG. 12;

FIG. 5 is a cross-sectional view of the steering unit taken through avertical mid-plane, where the steering wheel is in the lifted positioncorresponding to the inactive position of the command member of thecontrol unit shown in FIG. 3;

FIG. 6 is a cross-sectional view of the steering unit taken through avertical mid-plane, where the steering wheel is in the lowered positioncorresponding to the active position of the command member of thecontrol unit shown in FIG. 4;

FIG. 7 is a top view of the control unit with some parts sectioned,where the command member is in a neutral position corresponding to thestraight position of the steering wheel of the steering unit shown inFIG. 9;

FIG. 8 is a top view of the control unit with some parts sectioned,where the command member is in a rotated position corresponding to therotated position of the steering wheel of the steering unit shown inFIG. 10;

FIG. 9 is a top view of the steering unit with some parts sectioned,where the steering wheel is in a straight position corresponding to theneutral position of the command member of the control unit shown in FIG.7;

FIG. 10 is a top view of the steering unit with some parts sectioned,where the steering wheel is in a rotated position corresponding to therotated position of the command member of the control unit shown in FIG.8;

FIG. 11 is a cross-sectional view of a steering unit according to analternative embodiment taken through a vertical mid-plane, where thesteering wheel is in the lifted position;

FIG. 12 is a cross-sectional view of the steering unit of FIG. 11 takenthrough a vertical mid-plane, where the steering wheel is in the loweredposition;

FIG. 13 is a front view of the control unit according to an alternativeembodiment, with some parts sectioned, where the command member is in aninactive position corresponding to the lifted position of the steeringwheel of the steering unit shown in FIG. 5 or in FIG. 11;

FIG. 14 is a front view of the control unit of FIG. 13, with some partssectioned, where the command member is in an active positioncorresponding to the lowered position of the steering wheel of thesteering unit shown in FIG. 6 or in FIG. 12;

FIG. 15 is a top view of the control unit of FIG. 13, with some partssectioned, where the command member is in a neutral positioncorresponding to the straight position of the steering wheel of thesteering unit shown in FIG. 9; and

FIG. 16 is a top view of the control unit of FIG. 13, with some partssectioned, where the command member is in a rotated positioncorresponding to the rotated position of the steering wheel of thesteering unit shown in FIG. 10.

FIGS. 17 and 18 are cross sectional views of the steering units of analternative embodiment to the one depictures in FIGS. 5 and 6.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

With reference first to FIG. 1, it generally shows a chassis of ahuman-driven vehicle to which a steering assembly according to anembodiment of the present invention is applied. The mentioned vehicleshown in FIG. 1 is exemplified by a shopping cart having a chassis 1with a first end region 1 a and a second end region 1 b, which areopposite to one another. According to a forward movement direction ofthe vehicle in usual conditions the mentioned first and second endregions 1 a, 1 b correspond to a rear end region and a front end region,respectively. The chassis 1 is mounted on four freely rotating wheels 2,two of them located in the first end region 1 a and the other two in thesecond end region 1 b. In the shopping cart shown in FIG. 1 the fourwheels are self-orienting wheels 2, although for the purposes of thepresent invention it is only essential for the wheels located in thesecond end region 1 b to be self-orienting wheels 2. The chassis 1 ofthe shopping cart shown in FIG. 1 further includes a push structure inthe form of a substantially horizontal push member 3 fixedly joined tothe chassis 1 in the first end region 1 a, such that a user can manuallypush said push member 3 to make the cart move forwards, and the steeringassembly of the embodiment shown is configured to be applied to suchshopping cart provided with push member 3. It must be taken intoaccount, however, that the steering assembly of the present inventioncould alternatively be configured to be applied to any type ofhuman-driven vehicle provided with another type of push structure.

In general terms, the steering assembly of the present inventioncomprises a fifth wheel or steering wheel 4 installed on a wheel support5 (better shown in FIGS. 5, 6 and 9-11) in the second end region 1 b ofthe chassis 1, a lowering mechanism which can be manually operated tomove said wheel support 5 between a lifted position (FIGS. 5 and 11), inwhich said steering wheel 4 is out of contact with the ground, and alowered position (FIGS. 6 and 12), in which the steering wheel 4 is incontact with the ground; and a steering mechanism which can be manuallyoperated to make the wheel support 5 and with it the steering wheel 4rotate with respect to a steer shaft 12, which is in a substantiallyvertical position at least when the wheel support 5 is in said loweredposition, to steer the vehicle. Each of said lowering and steeringmechanisms has a first part installed in association with a commandmember 7 in said first end region 1 a of the chassis 1 and a second partinstalled in association with the wheel support 5 and the steering wheel4 in the second end region 1 b of the chassis 1. The mentioned first andsecond parts of the lowering and steering mechanisms are connected toone another by respective first and second movement transmission devices19, 20, 21 (symbolically depicted in FIG. 1).

The mentioned command member 7 is capable of performing combinedrotation movements on two axes and serves both for the loweringmechanism and for the steering mechanism, such that the command member 7can be manually operated by a user to remotely perform the lowering androtation movements of the wheel support 5 and steering wheel 4 from aposition adjacent to said push structure or push member 3. The steeringassembly comprises first elastic means (which will be described indetail below) arranged to push the wheel support 5 towards said liftedposition and maintain it therein. The lowering mechanism is configuredto move, as a consequence of a manual operation thereof, the wheelsupport 5 towards the lowered position, and maintain it therein, againstthe force of said first elastic means. Therefore, when the mentionedmanual operation of the lowering mechanism ceases, the first elasticmeans automatically return the wheel support 5 to the lifted position.Furthermore, the command member can be manually operated to performvariation movements in the orientation of the wheel support 5 andsteering wheel 4 while the wheel support 5 is maintained in the loweredposition to steer the vehicle.

The first parts of the lowering and steering mechanisms together withthe command member 7 are integrated in a control unit 50 a configured tobe fixed to the push structure or to the chassis 1 in the first endregion 1 a, and the second parts of the lowering and steering mechanismstogether with the steering wheel 4 are integrated in a steering unit 50b configured to be fixed to the chassis 1 in the second end region 1 b.In the embodiment shown in the figures, the mentioned control unit 50 ais configured to be fixed to the push member 3 and the command member 7,which has the form of a handlebar formed by an elongated rigid body 35provided with a pair of grips 7 a, 7 b at its opposite ends, ispositioned on one side of the push member 3 facing the front region orsecond end region 1 b of the chassis 1. When the control unit 50 a isfixed in an operative position, the grips 7 a, 7 b of the command memberare located at a suitable distance from the push member 3 so that theycan be operated with one or more fingers of each hand at the same timeas the vehicle is pushed with the palms and the thumbs of the hands onthe push member 3. Alternatively, the control unit 50 a could be fixedto the chassis 1 in a position adjacent to the push member 3 such thatthe grips 7 a, 7 b were in the position described in relation to thepush member 3. In human-driven vehicles without a push member, thecontrol unit 50 a could be fixed in the corresponding push structure orin the chassis 1 close to the push structure and the command member 7could have a form different from a handlebar.

FIG. 2 separately shows the control unit 50 a and the steering unit 50 binterconnected by said first and second movement transmission devices19, 20, 21, which are formed by Bowden type flexible cable and sheathassemblies 19 a, 19 b; 20 a, 20 b; 21 a, 21 b. The control unit 50 acomprises a first base body 15 configured to be fixed to the upper sideof the push member 3 by means of a lower clamp part 46 (see also FIGS. 3and 4). The elongated rigid body 35 forming the command member 7 has anintermediate portion between the grips 7 a, 7 b fixed to a steeringcontrol support 8, which is mounted such that it can rotate with respectto a substantially vertical steering control shaft 13 supported in alowering control support 9. The mentioned lowering control support 9 isin turn mounted such that it can rotate with respect to a loweringcontrol shaft 14 which is substantially horizontal and substantiallyparallel to the longitudinal direction of the elongated rigid body 35,said lowering control shaft 14 being supported in said first base body15. Thus, the command member 7 is provided with combined rotationmovements on two crossed axes, namely; the axes of the steering controlshaft 13 and the lowering control shaft 14. Optionally, in the firstbase body 15 of the control unit 50 a there is operatively housed acoin-operated locking device 45 for allowing the immobilization of thevehicle with respect to another vehicle with a similar coin-operatedlocking device, or with respect to an anchoring point fixed in relationto the ground. The mentioned coin-operated locking device 45 can be of acommercially available conventional type comprising an anchoring part 48secured by a chain 49 or another flexible element, an anchoring slot(not shown) for the introduction of a similar anchoring part secured toan adjacent cart or to a fixed anchoring point, a mechanism forimmobilizing said anchoring part 48 in said anchoring slot, and a coinslot 51 for the introduction of a coin releasing said immobilizationmechanism. The steering unit 50 b comprises a second base body 17configured to be fixed, for example, to the lower side of a plate 47(FIG. 1) joined to the chassis 1.

FIGS. 3 and 4 show a cross-sectional view of the control unit 50 a withthe command member 7 fixed to the steering control support 8, which isrotationally installed on the lowering control support 9, which is inturn mounted such that it can rotate with respect to said loweringcontrol shaft 14 supported in the first base body 15. Between thesteering control support 8 and the lowering control support 9 of thecontrol unit 50 a there are arranged second elastic means 22 a, 22 b topush the steering control support 8 and the command member 7 fixedthereto towards a neutral position corresponding to a straightorientation of the driving wheel 4. The mentioned first part of thelowering mechanism housed in the control unit 50 a comprises a loweringlever 23 mounted to rotate in its middle part with respect to a pin 24supported in the first base body 15. This lowering lever 23 has an endprovided with a pin 25 inserted to run in a guided manner in a guideslot 26 formed in the lowering control support 9 and another oppositeend provided with a first engagement configuration 27 for engaging afirst end of the cable 19 a of the first movement transmission device19, whereas a first end of the sheath 19 b of the first movementtransmission device 19 is retained in a housing 52 of the first basebody 15. Thus, a manually applied downward force on the control member 7makes the lowering control support 9 rotate about the lowering controlshaft 14, and the lowering control support 9 in turn makes the loweringlever 23 rotate about the pin 24, and the lowering lever 23 pulls on thefirst end of the cable 19 a of the first movement transmission device19, as shown in FIG. 4. In other words, the first part of the loweringmechanism arranged in the control unit 50 a is capable of transforming arotation of the lowering control support 9 with respect to the loweringcontrol shaft 14 into an axial movement of the cable 19 a of said firstmovement transmission device 19.

With reference now to FIGS. 5 and 6, the second part of the loweringmechanism integrated in the steering unit 50 b is described, which isconfigured and arranged to transform the movement of the first movementtransmission device 19 into a pivoting of the rocker support 6 withrespect to said first substantially horizontal shaft 16 and thus movethe wheel support 5 to said lowered position, in which the steeringwheel 4 is in contact with the ground, against the force of the firstelastic means. The second base body 17 of the steering unit 50 bsupports a substantially horizontal rocking shaft 16 with respect towhich a rocker support 6 can pivot. This rocker support 6 in turnsupports the mentioned steer shaft 12 with respect to which the wheelsupport 5 can rotate, where the wheel support 5 has the steering wheel 4mounted such that it can rotate with respect to a wheel shaft 55supported in a yoke 56. The mentioned first elastic means comprise acoil spring 10 arranged under traction between the rocker support 6 andsaid second base body 17 of the steering unit 50 b to maintain therocker support 6, the wheel support 5 and the steering wheel 4 in thelifted position shown in FIG. 5. The second part of the loweringmechanism arranged in the steering unit 50 b comprises an articulatedarm having a first member 28 mounted to pivot with respect to a firstpin 29 supported in the second base body 17 of the steering unit 50 band a second member 30 mounted to pivot with respect to a second pin 31supported in the rocker support 6. The mentioned first and secondmembers 28, 30 are articulately connected to one another by means of athird pin 32, and said articulated arm includes a second engagementconfiguration 33, formed for example in said third pin 32, for engaginga second end of said cable 19 a of the first movement transmissiondevice 19, whereas a second end of the sheath 19 b of the first movementtransmission device 19 is retained against a wall of the second basebody 17. Thus, the second part of the lowering mechanism arranged in thesteering unit 50 b is capable of transforming the mentioned axialmovement of the cable 19 a of the first movement transmission device 19,caused by an action of the first part of the lowering mechanism arrangedin the control unit 50 a (FIG. 4) into a pivoting movement of the rockersupport 6 about the rocking shaft 16 to take the wheel support 5 to thelowered position, in which the steering wheel 4 is in contact with theground, against the force of the first elastic means (FIG. 6).

FIGS. 7 and 8 depict top views of the control unit 50 a without thelowering control support 9 to better show the first part of the steeringmechanism, which comprises a steering lever 36 mounted such that it canrotate with respect to a shaft 37 supported in the lowering controlsupport 9 (see FIGS. 3 and 4). This steering lever 36 has a first end inwhich there is formed a first gear wheel sector 38 concentric with saidshaft 37. The mentioned first gear wheel sector 38 is meshed with asecond gear wheel sector 39 formed in the steering control support 8,this second gear wheel sector 39 being concentric with the steeringcontrol shaft 13, which is likewise supported in the lowering controlsupport 9 (see FIGS. 3 and 4). A second end of the steering lever 36comprises a first pair of engagement configurations 36 a, 36 b forengaging first ends of two cables 20 a, 21 a forming part of the secondmovement transmission device 20, 21, whereas first ends of therespective sheaths 20 b, 21 b of the second movement transmission device20, 21 are retained in respective housings 53 a, 53 b formed in thefirst base part 15. Thus, the first part of the steering mechanismintegrated in the control unit 50 a is configured and arranged totransform the rotations of the steering control support 8 with respectto said steering control shaft 13 into axial movements of the cables 20a, 21 a of said second movement transmission device 20, 21.

In relation to FIGS. 9 and 10, the second part of the steering mechanismintegrated in the steering unit 50 b is described below, which isconfigured and arranged to transform said axial movements of said cables20 a, 21 a of the second movement transmission device 20, 21 intorotations of the wheel support 5 with respect to said steer shaft 12, tothus vary the orientation of the steering wheel 4 and steer the vehicle.This second part of the steering mechanism comprises a pulley 34 fixedto the wheel support 5 to rotate together with the wheel support 5 aboutthe steer shaft 12. The mentioned pulley 34 comprises a second pair ofengagement configurations 34 a, 34 b for engaging second ends of thecables 20 a, 21 a of the second movement transmission device 20, 21 anda circumferential groove 34 c on which portions of said cables 20 a, 21a of the second movement transmission device 20, 21 are supported.Second ends of the sheaths 20 b, 21 b of the second movementtransmission device 20, 21 are retained in respective housings 54 a, 54b of the rocker support 6, optionally in cooperation with elastic means.

The steering mechanism is preferably a multiplier mechanism, i.e., anangle rotated by the command member 7 with respect to the steeringcontrol shaft 13 is smaller than an angle rotated by the wheel support 5with respect to the steer shaft 12. Thus, a user can steer the vehiclewith slight movements of the fingers without letting go of the pushmember 3. In the embodiment shown in FIGS. 2 to 10, the mentionedmultiplier effect is achieved by suitably selecting the radii of saidfirst and second gear wheel sectors 38, 39 (FIGS. 7 and 8), thedistances from said first pair of engagement configurations 36 a, 36 bof the steering lever 36 to the corresponding shaft 37 (FIGS. 7 and 8)and the distances from said second pair of engagement configurations 34a, 34 b of the pulley 34 to the steer shaft 12 (FIGS. 9 and 10).

FIGS. 11 and 12 show an alternative embodiment for the second part ofthe steering mechanism integrated in the steering unit 50 b, which isconfigured and arranged to transform the movement of the first movementtransmission device 19 into a linear translation of the wheel support 5with respect to said shaft support 40 to the lowered position, in whichthe steering wheel 4 is in contact with the ground, against the force ofthe first elastic means. Here, the wheel support 5 is linked to a linearguide arrangement such that it can slide in a direction parallel to thesteer shaft 12 with respect to a shaft support 40 supporting the steershaft 12. The mentioned shaft support 40 is supported in the second basebody 17 of the steering unit 50 b, and said second base body 17 isconfigured to be fixed to the chassis 1.

In this alternative embodiment for the second part of the steeringmechanism, the pulley 34 is mounted on the shaft support 40 such that itcan rotate about but not slide along the steer shaft 12, and drive rods41 parallel to the steer shaft 12 are fixed to the wheel support 5 andslidingly inserted in corresponding holes 42 formed in the pulley 34.The first elastic means here comprise coil springs 18 arranged aroundsaid drive rods 41 such that they can be compressed between end stops 41a of the drive rods 41 and the pulley 34. A rotation of the pulley 34 asa consequence of the action of the second movement transmission device20, 21 is transmitted to the wheel support 5 by the drive rods 41whatever the position of the wheel support 5 in the vertical direction.In this alternative embodiment, the second part of the loweringmechanism comprises a cam 43 mounted such that it can rotate withrespect to a shaft 44 supported in the second base body 17 of thesteering unit 50 b. The mentioned cam 43 is provided with an eccentricprofile 43 a arranged to press against the wheel support 5 and a secondengagement configuration 43 b for engaging a second end of the cable 19a of the first movement transmission device 19.

FIGS. 13 to 16 show an alternative embodiment for the first parts of thelowering and steering mechanisms integrated in the control unit 50 a. Inthis alternative embodiment, the command member 7 comprises twoelongated rigid bodies 35 a, 35 b, each of which has a grip 7 a, 7 b ata distal end and is fixed at an opposite proximal end to a correspondinglowering control shaft 14 a, 14 b which is substantially horizontal andsubstantially perpendicular to the longitudinal direction of theelongated rigid body 35 a, 35 b. These lowering control shafts 14 a, 14b are mutually parallel and are supported such that they can rotate on asteering control support 8, which is fixed to a steering control shaft13. The mentioned steering control shaft 13 is supported such that itcan rotate in a substantially vertical position on a first base body 15of the control unit 50 a, which is configured to be fixed to the pushmember 3 of the chassis 1, although alternatively said first base body15 could be fixed to the chassis 1 in a position adjacent to the pushmember 3.

With this construction, the two elongated rigid bodies 35 a, 35 bforming the command member 7 can be manually rotated in oppositedirections about the respective lowering control shafts 14 a, 14 bbetween lifted positions (FIG. 13) and lowered positions (FIG. 14), andthe command member 7 together with the steering control support 8 can bemanually rotated in opposite directions about the steering control shaft13 between a neutral position (FIG. 15) and positions rotated to theleft (FIG. 16) and to the right (not shown).

The first part of the lowering mechanism of this alternative embodimentcomprises a pair of first gear wheel sectors 60 a, 60 b fixedrespectively to the lowering control shafts 14 a, 14 b and meshed withrespective racks 61 a, 61 b formed on opposite sides of a tractionelement 61 installed such that it can move in a vertical direction withrespect to the steering control support 8. The mentioned tractionelement 61 is fixed to a first end of the cable 19 a of the firstmovement transmission device 19. The steering control shaft 13 has aninner cavity and a side opening 13 a through which the cable 19 a andthe sheath 19 b of the first movement transmission device 19 areintroduced. In a wall of the upper end of the steering control shaft 13there is formed an axial hole through which the cable 19 a passes,whereas the sheath 19 b is retained by said wall of the upper end of thesteering control shaft 13. The steering control support 8, the loweringcontrol shafts 14 a, 14 b, the gear wheel sectors 60 a, 60 b and thetraction element 61 are protected by a casing 67.

Thus, this first part of the lowering mechanism transforms rotations inopposite directions of the lowering control shafts 14 a, 14 b into anaxial movement of the cable 19 a of the first movement transmissiondevice 19. The coil spring 10 (FIGS. 5 and 6) or the coil springs 18(FIGS. 11 and 12) providing the first elastic means in the steering unit50 b pull on the cable 19 and push the two elongated rigid bodies 35 a,35 b forming the command member 7 towards the lifted position (FIG. 13).Optionally, an additional spring (not shown) is arranged to push thetraction element 61 downwards.

It will be understood that in the embodiment shown in FIGS. 13 to 16 thecommand member 7 could alternatively comprise only one elongated rigidbody connected to a single lowering control shaft fixed to a single gearwheel sector meshed with a single rack fixed to the first end of thecable with an equivalent result.

The first part of the steering mechanism of the alternative embodimentshown in FIGS. 13 to 16 comprises a second gear wheel sector 62 fixed tothe steering control shaft 13 and meshed with a pinion 63 fixed to anauxiliary shaft 64 parallel to the steering control shaft 13. A pulley65 is fixed to said auxiliary shaft 64, and first ends of the cables 20a, 21 a of the second movement transmission device 20, 21 are fixed onsaid pulley 65, whereas the corresponding sheaths 20 b, 21 b areretained in a stop wall 66 fixed with respect to the first base body 15of the control unit 50 a. Thus, this first part of the steeringmechanism transforms rotations of the steering control support 8together with the steering control shaft 13 into axial movements of thecables 20 a, 21 a of the second movement transmission device 20, 21.

The embodiment with gear wheel sector 62 meshed with a pinion 63providing a de-multiplying effect can be substituted with a pulley 65directly fixed to the steering control shaft 13, by an adequateselection of the diameter of said pulley 65 and pulley 34 fixed to thewheel support 5 to rotate together with the wheel support 5 about thesteer shaft 12.

In the alternative embodiment of the guiding member 7 shown in FIGS. 13to 16, the incorporation of a coin-operated locking device 45operatively housed in said first base body 15 of the control unit 50 a(FIGS. 13 and 14) has also foreseen.

FIGS. 17 and 18 show and alternative embodiment of the loweringmechanism arranged in the steering unit 50 b capable of transforming thementioned axial movement of the cable 19 a of the first movementtransmission device 19, caused by an action of the first part of thelowering mechanism arranged in the control unit 50 a (FIG. 4) into apivoting movement of the rocker support 6 about the rocking shaft 69 totake the wheel support 5 to the lowered position, in which the steeringwheel 4 is in contact with the ground, against the force of the firstelastic means 10 (FIG. 17). In this alternative embodiment when thewheel is not contacting with the ground is shifted to the rear, insteadof advanced as in FIG. 5. This is obtained thanks to an L-shaped lever68 pivoted on rocking shaft 69 and linked by one end to a spring 10 andattached to the other end by cable 19 a. Spring 10 is extended betweenretaining lugs 70 and 71 as seen in the Figs.

A person skilled in the art will be able to make modifications andvariations from the embodiments shown and described without departingfrom the scope of the present invention as it is defined in the attachedclaims.

1. A steering assembly for a human-driven vehicle, said vehicle having achassis (1) mounted on a plurality of freely rotating wheels, wherein atleast two of said freely rotating wheels are self-orienting wheels (2)located in an end region of the chassis (1), said steering assemblycomprising: a steering wheel (4) installed on a wheel support (5) in thesame end region of the chassis (1) as said two self-orienting wheels(2); a manually operable lowering mechanism for moving said wheelsupport (5) between a lifted position, in which said steering wheel (4)is out of contact with the ground, and a lowered position, in which thesteering wheel (4) is in contact with the ground; and a manuallyoperable steering mechanism for making the wheel support (5) and with itthe steering wheel (4) rotate with respect to a steer shaft (12); firstelastic means arranged to push the wheel support (5) towards said liftedposition; a common command member (7) for said lowering mechanism andsaid steering mechanism, which can be manually operated to move thewheel support (5) towards the lowered position against the force of saidfirst elastic means and to rotate the wheel support (5) with respect tosaid steer shaft (12); and a first movement transmission device (19)arranged to transmit lowering movements from the command member (7) tothe wheel support (5) and a second movement transmission devices (20,21) is arranged to transmit steering movements from the command member(7) to the wheel support (5), characterized in that said command member(7) is located in a first end region (1 a) of the chassis (1) and thewheel support (5) with the steering wheel (4) is located in a second endregion (1 b) of the chassis (1) opposite to said first end region (1 a);the lowering and steering mechanisms comprises a first part connected tosaid command member (7) in said first end region (1 a) of the chassis(1) and a second part connected to the wheel support (5) in said secondend region (1 b) of the chassis (1), and said first and second movementtransmission devices (19, 20, 21) transmit movements from said firstparts of the lowering and steering mechanisms connected to the commandmember (7) to said second parts of the lowering and steering mechanismsconnected to the wheel support (5); and the first parts of the loweringand steering mechanisms are integrated in a control unit (50 a)configured to be fixed to a push member (3) connected to the chassis (1)or to the chassis (1) in a position adjacent to said push member (3) inthe first end region (1 a), and the wheel support (5) with the steeringwheel (4) and the second parts of the lowering and steering mechanismsare integrated in a steering unit (50 b) configured to be fixed to thechassis (1) in the second end region (1 b).
 2. The assembly according toclaim 1, characterized in that said first and second movementtransmission devices (19, 20, 21) comprise flexible cable and sheathassemblies (19 a, 19 b; 20 a, 20 b; 21 a, 21 b).
 3. The assemblyaccording to claim 1, characterized in that: the command member (7) canbe manually pivoted with respect to a substantially horizontal loweringcontrol shaft (14, 14 a, 14 b) and with respect to a substantiallyvertical steering control shaft (13); the first part of the loweringmechanism integrated in the control unit (50 a) is configured andarranged to transform a rotation of the command member (7) with respectto said lowering control shaft (14, 14 a, 14 b) into an axial movementof a cable (19 a) of said first movement transmission device (19), andthe second part of the lowering mechanism integrated in the steeringunit (50 b) is configured and arranged to transform said axial movementof said cable (19 a) of the first movement transmission device (19) intoa movement of the wheel support (5) towards said lowered positionagainst the force of the first elastic means; and the first part of thesteering mechanism integrated in the control unit (50 a) is configuredand arranged to transform rotations of the command member (7) withrespect to said steering control shaft (13) into axial movements ofcables (20 a, 21 a) of said second movement transmission device (20,21), and the second part of the steering mechanism integrated in thesteering unit (50 b) is configured and arranged to transform said axialmovements of said cables (20 a, 21 a) of the second movementtransmission device (20, 21) into rotations of the wheel support (5)with respect to said steer shaft (12) to thus vary the orientation ofthe steering wheel (4) and steer the vehicle.
 4. The assembly accordingto claim 3, characterized in that the command member (7) comprises atleast one elongated rigid body (35 a, 35 b) having a distal end with agrip (7 a, 7 b) and a proximal end fixed to a lowering control shaft (14a, 14 b) which is substantially horizontal and substantiallyperpendicular to the longitudinal direction of the elongated rigid body(35 a, 35 b), said lowering control shaft (14 a, 14 b) is supported suchthat it can rotate on a steering control support (8) fixed to asubstantially vertical steering control shaft (13), which is supportedsuch that it can rotate on a first base body (15) of the control unit(50 a), and said first base body (15) is configured to be fixed to saidpush member (3) or to the chassis (1).
 5. The assembly according toclaim 4, characterized in that said first part of the lowering mechanismcomprises at least one first gear wheel sector (60 a, 60 b) fixed to thelowering control shaft (14 a, 14 b) and meshed with a rack (61 a, 61 b)fixed to a first end of said cable (19 a) of the first movementtransmission device (19), and said first part of the steering mechanismcomprises a second gear wheel sector (62) fixed to the steering controlshaft (13) and meshed with a pinion (63) fixed to an auxiliary shaft(64), and a pulley (65) fixed to said auxiliary shaft (64) and on whichthere are fixed first ends of the cables (20 a, 21 a) of the secondmovement transmission device (20, 21).
 6. The assembly according toclaim 3, characterized in that the command member (7) comprises anelongated rigid body (35) having opposite ends with a pair of grips (7a, 7 b) and an intermediate portion fixed to a steering control support(8) mounted such that it can rotate with respect to a substantiallyvertical steering control shaft (13) supported in a lowering controlsupport (9), said lowering control support (9) is mounted such that itcan rotate with respect to a lowering control shaft (14) which issubstantially horizontal and substantially parallel to the longitudinaldirection of the elongated rigid body (35), said lowering control shaft(14) is supported in a first base body (15) of the control unit (50 a),and said first base body (15) is configured to be fixed to said pushmember (3) or to the chassis (1).
 7. The assembly according to claim 6,characterized in that said first part of the lowering mechanismcomprises at least one lowering lever (23) mounted to rotate withrespect to a pin (24) supported on the first base body (15) of thecontrol unit (50 a), said lowering lever (23) has a portion linked tothe lowering control support (9) to be moved by it and another portionconnected to a first end of said cable (19 a) of the first movementtransmission device (19), and said first part of the steering mechanismcomprises a steering lever (36) mounted to rotate with respect to ashaft (37) supported in the lowering control support (9) of the controlunit (50 a), wherein said steering lever (36) has a first gear wheelsector (38) concentric with said shaft (37) and meshed with a secondgear wheel sector (39) formed in the steering control support (8) andconcentric with the steering control shaft (13), and is connected tofirst ends of the cables (20 a, 21 a) of the second movementtransmission device (20, 21).
 8. The assembly according to claim 1,characterized in that said second part of the lowering mechanismcomprises a rocker support (6) mounted such that it can pivot withrespect to a substantially horizontal rocking shaft (16) supported on asecond base body (17) of the steering unit (50 b) configured to be fixedto the chassis (1), said steer shaft (12) with respect to which thewheel support (5) can rotate is supported on said rocker support (6),and an articulated arm (28, 30) linked to said second base body (17) andto the rocker support (6) is connected to a second end of said cable (19a) of the first movement transmission device (19), and said second partof the steering mechanism comprises a pulley (34) mounted to rotatetogether with the wheel support (5) about the steer shaft (12), whereinsaid pulley (34) has fixed thereto second ends of the cables (20 a, 21a) of the second movement transmission device (20, 21).
 9. The assemblyaccording to claim 8 characterized in that the first elastic meanscomprise at least one coil spring (10) arranged between the rockersupport (6) and said second base body (17) of the steering unit (50 b).10. The assembly according to claim 1, characterized in that said secondpart of the lowering mechanism comprises a shaft support (40) supportedin a second base body (17) of the steering unit (50 b) configured to befixed to the chassis (1), the steer shaft (12) to which the wheelsupport (5) is fixed is supported such that it can rotate and slideaxially with respect to said shaft support (40) between the lifted andlowered positions, and a second end of said cable (19 a) of the firstmovement transmission device (19) is connected to at least one cam (43)mounted in the second base body (17) and arranged to press the wheelsupport (5) towards the lowered position, and said second part of thesteering mechanism comprises a pulley (34) mounted on the shaft support(40) such that it can rotate about but not slide in parallel to thesteer shaft (12), and at least one drive rod (41) parallel to the steershaft (12) is fixed to the wheel support (5) and slidingly inserted in ahole (42) formed in said pulley (34), wherein said pulley (34) has fixedthereto second ends of the cables (20 a, 21 a) of the second movementtransmission device (20, 21) and wherein said drive rod (41) transmitsthe rotations of the pulley (34) to the wheel support (5).
 11. Theassembly according to claim 10, characterized in that the first elasticmeans comprise at least one coil spring (18) arranged around said driverod (41) between a stop (41 a) joined to the end of the drive rod (41)and the pulley (34).
 12. The assembly according to claim 1,characterized in that a coin-operated locking device (45) is operativelyhoused in a first base body (15) of said control unit (50 a) to allowthe immobilization of the vehicle with respect to another vehicle with asimilar coin-operated locking device, or with respect to an anchoringpoint fixed in relation to the ground.
 13. A human-driven vehicle, ofthe type comprising a chassis (1) with a first end region (1 a) and asecond end region (1 b) which are opposite to one another, said chassis(1) being mounted on freely rotating wheels, wherein at least two ofsaid wheels, which are located in said second end region (1 b), areself-orienting wheels (2), characterized in that said vehicle includes asteering assembly according to claim
 1. 14. A kit to be incorporated topre-existing vehicles comprising at least a steering assembly accordingto claim 1.